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by WHITE BEAR on April 12th, 2007

WHITE BEAR

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What is the deepest from which you could exit a doomed submarine by swimming out the hatch to the surface with no diving gear?

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Answers. 6 helpful answers below.

  • by The Chief on October 18th, 2009

    The Chief

    oldsubguy and Bubblehead have it very close.

    Not too long ago, emergency evacuation of submerged submarines by the crew took place using what was called the "Steinke hood".

    Essentially, this was a bare-bones plastic hood you wore over your head, which had a clear plastic part you could see though. You put the hood on, entered the escape trunk, shut the lower hatch, and kept the hood filled with air as the escape trunk was filled with water. There is a steel skirt around the upper hatch where you could breathe the air as the water filled the trunk and the trunk equalized with sea pressure.

    With the Steinke hood on and filled with pressurized air from the escape trunk, you would then immediately open the upper hatch and exit, one man at a time, and head for the surface. Last man out signaled with a hammer when all were clear so the hatch could be shut by the rest of the crew in the sub, the trunk drained, and then the cycle repeated for the next group.

    The Steinke provided positive bouyancy, which pulls you to the surface. And while this is going on, it is vitally important to realize exactly what it happening as you ascend.

    At depth, you are breathing air at potentially several hundred pounds of pressure per square inch. As you rise in the water, sea pressure drops and this air expands. Excess air is vented out of the Steinke hood as you rise.

    This means there is more than enough air for the Sailor to breathe as he ascends from the depths...he will NOT run out. In fact, he is trained to force air OUT of his lungs during the entire ascent to prevent the air he's breathing from expanding and damaging his lungs.

    And yes, he's trained to do this by saying "HO-HO-HO" like Santa Clause. This gives him an audible indication to focus on to ensure he's breathing out correctly.

    On the way up, he holds his arms above his head, clasped hand to hand, to prevent slamming his head into someone or something on the way up.

    Now-a-days the Steinke Hood is no longer used. The SEIE (Submarine Escape Immersion Equipment) is used.

    http://en.wikipedia.org/wiki/Submarine_Escape_Immersion_Equipment

    Instead of a hood, the SEIE is an entire survival suit which is used similar to the Steinke Hood when escaping. Only now, with the SEIE, each Sailor has his own miniature life raft, complete with a sealable canopy, that will keep him dry and warm. It is a full body, thermally insulated suit AND raft.

    This system may be used at depths of up to 600 feet.

    One may be concerned about the "bends", which divers must be trained for. "Bends" occurs when nitrogen, absorbed into the tissues by breathing air under pressure, starts to come out of solution in the blood and joints as sea pressure decreases.

    However, this is part of the 600 foot limit. How much nitrogen is absorbed into the tissues depends both on the pressure of the air being breathed and the time the air is breathed.

    The short duration required to breathe the high pressure air from the time the escape trunk it pressurized to the time it takes to exit and reach the surface is minimized with this in mind. Thus the maximum depth is considered to be 600 feet.

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  • by 8 Jan 2004-10 Dec 2009 on April 12th, 2007

    8 Jan 2004-10 Dec 2009

    A tricky question.

    There are many variables, including but not limited to the person's level of fitness, ability to hold their breath, internal hull pressure before escaping, dumb luck....

    While fit, trained free-divers may be able to come up from over 500 feet down without issue, most people would be lucky to survive 50 feet, at least without serious decompression issues. A trained submarine crewmember will likely have trained to fare a bit better, but over 200 feet is pushing it.

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  • by Persky Bunkermeister on April 12th, 2007

    Persky Bunkermeister

    Competition free divers can dive down over 500 feet in one breath. For those depths you have to be able to hold your breath for over 2 minutes. (http://www.smh.com.au/articles/2003/10/13/1065917309678.html?from=storyrhs)
    You go up a lot quicker than you go down, so the submarine hatch escape is really about how long you can hold your breath. It's also about keeping your calm, staying out of the path of sharks and jelly fish and using as little energy as possible (to preserve the supply of oxygen to your brain).

    My guess is that considering the described conditions, and the fact that you'd have no time to practice holding your breath -- you'd have to be in pretty good shape to hold your breath much over a minute... you might make it up from 500 feet.

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  • by ChrisDG on April 12th, 2007

    ChrisDG

    Before I answer this, I should point out this is all educated conjecture on my part, so don't blame me if you fail a TV quiz show for getting this wrong based on my answer.

    This answer depends on the individual, since it depends on the ability to hold breath, the size of the person's lungs and their ability to swim and various other factors.

    The deeper you go down below the water surface, the greater the pressure increases, by one atmosphere about every 10 metres. So 10m, your body is compressed by the water around it at a pressure of two atmospheres, i.e. twice the pressure you experience when on land. At this depth, you can already feel the water pressing around you, and the pressure will also act on the gases in your body, so the air in your lungs will be compressed to a smaller volume than what you would find on land.

    However, because you took your last breath in the pressurised airlock in the submarine (one would hope!) before entering the water, the actual amount of air, and so amount of oxygen in your lungs is still the same, it just occupies a smaller volume. So although the physics of bloodflow and gas exchnage across the capillary membranes will be affected by pressure, at this depth it shouldn't matter too much.

    As you get deeper and deeper in this hypotehtical situation, the pressures build up and up until they would crush your body into a tiny little mess of tissue. However, at this depth, it is likely that were you not crushed, you would not have been able to hold your breath for the time it took to come up to the surface anyway.

    If you consider freedivers, they can descend and (usually) reascend to incredible depths on just one breath. They train to utilise as much of the oxygen in their lungs as possible and ignore the effects of the lactic acid buildup caused by anaerobic respiration in their muscles. The pressure isn't a problem with regards to their oxygen levels because they took on air at a "normal" air pressure before diving, and the same (or similar) would apply from a submarine. All the diving gear is doing in the most basic sense is to prolong the time you could spend under the water by increasing the amount of availble oxygen to you (though drysuits do allow you to create a buffer between the prssure of the water and your body).

    So I would imagine that the answer basically depends on the individuals ability to hold their breath and swim up to the surface. Don't forget the light levels decrease as you descend and that you may not realise which direction up actually is when you leave the submarine, so a helpful neon pointer would also be beneficial.

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  • by oldsubguy on July 12th, 2008

    oldsubguy

    Well, almost every answer I've read to the submarine questions is just wrong. I'm a submariner. Yes, I have my dolphins. Submarine sailors are trained to escape from the boat by actually going through the drill. You escape by entering an escape hatch which is pressurized very quickly. You wear a hood/vest device called a Steinke Hood which lets out air at a predetermined rate. You then exit the boat and hold your arms in a certain way. During the ascent, you chant "ho, ho, ho" in a specific rythym that equalizes pressure in the lungs. It works. I won't discuss the depths, but you can imagine "deep". Beyond the maximum escape depth, you wouldn't need to worry about escaping. That mental problem would be cured in a split second. Some people can live with those concerns and do their job at sea, and a lot of people cannot.

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  • by Bubblehead on February 13th, 2008

    Bubblehead

    Some years ago a friend of mine who was an instructor in the Submarine Escape Training Tank (SETT) in HMS Dolphin, with several other instructors made an practise escape from 580 feet from an 'O' class submarine in the Med. They wore the standard submarine escape survival suit.
    There are mentions in the above answers of holding your breath, sorry but this is impossible.
    At any depth of water the water pressure on the escape hatch is too great to permit the hatch to be opened. The only way to counteract this is to flood the escape compartment until the air pressure in the compartment is equal to the water pressure outside
    a canvas tube is rigged from the escape hatch to a level below the water level in the compartment, when the escape hatch is opened the water coming in is limited to the canvas tube by the air pressure in the compartment, escapers can then duck under the tube and make a free ascent. therefore the air they have been breathing in the compartment is at the same pressure as the surrounding water. As the escaper is taken to the surface by a boyancy aid the water pressure decreases, which causes the air in his lungs to expand, unless the escaper blows this air out, in theory, he could burst his lungs.
    So, no swimming to the surface and no holding your breath.

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